Needs rear main seal replaced at the very least. Is that diamond plating or a rubber mat in the back?

https://austin.craigslist.org/cto/d/jeep-cj2a-1947/6556581754.html

“1947 willys jeep cj2a has New: upper water hose, steering wheel, shift knobs, gas tank, gauges, head lights, tails lights, rear view mirrors, seat covers, tires like new, spare is new, boot on shifter, spark plugs, master cylinder, fan belt, has been switched from 6v to 12v, has new brake lines just not installed, in damn good shape for 71 years old.has some leaks Needs rear main seal replaced. Looking for a good home don’t have the time to spend on it like I would. Also have chiltons book for the jeep.”